Consistently name client interfaces

[invidian]

Expected Behaviour

One can easily switch between working on code around workflows and templates and naming should follow the same convention, so interface names are not surprising, following POLA.

Current Behaviour

• github.com/tinkerbell/tink/protos/workflow has WorkflowSvcClient
• github.com/tinkerbell/tink/protos/hardware has HardwareServiceClient
• github.com/tinkerbell/tink/protos/template has TemplateClient

[mmlb]

100% yes!

[mmlb]

Thanks @invidian take a look at #345 which addresses this along with other protobuf related warts I encountered.